Steam generator



Dec. 31, 1929. E. J, RQwAN 1,741,657

STEAM GENERATOR Filed April 30 1927 T'HE- l INVENToR. Lm L \7 EUGENE J. ROWAN Patented Dec. 31, 1829 UNITED STATES EUGENE J. ROIVAN, OF ROCKVILLE CENTER, NEW YORK STEAM GENERATOR Application filed April 30,

The invention relates in general to a steam generator of general application and the invention particularly relates to steam boilers of the type designed for domestic household use where the source of heat is a gas burner.

In such domestic heating plants it is usually required that a limited amount of low pressure steam be generated constantly over long periods of time and on the ground of economy in operation it is required that the least amount of gas be supplied to the burner over prolonged time lapses. Itis also required in suoli structures that the heater as a whole be confined within a limited space and that the component parts, particularly the burner, be of small size and with a relatively low gas consumption.

The primary object of the invention is to rovide a gas-heated boiler for generating steam in limited quantities economically and to provide for increased efficiency in gas consumption compared to the steam generated.

An incidental object of the invention is to provide for the complete or substantially complete abstraction of all of the heat units from the` burning gases and to utilize the maximum number of such heat units, first in a pre-heating of the water supplied to the boiler and, finally an intense heating of small 3o portions of the preheated water in order to generate steam at the requisite pressure and temperature. Y

Still another object of the invention is to provide a heat reservoir which will at all times, after the device has been once started, maintain a large amount of heat, preferably at high temperature, in intimate Contact with the steam generating` tubes so that these tubes will at all times be exposed to a large volume of thermal units, irrespective of the activity at the time of the burner.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of mechanism embodying my invention, and the invention also consists in certain new and novel features of construction and com- 1927. Serial No. 188,038.

bination of parts hereinafter set forth and claimed.

In the accompanying drawing:

Fig. 1 is a view largely in vertical, axial section through a domestic heating boiler .constituting a preferred embodiment of the invention;

Fig. 2 is a horizontal, sectional view taken on the plane indicated by the line 2-2 and looking downwardly in the direction indicated by the arrows and showing part of the baille broken away; and

Fig. 3 is a detailed view, partly in elevation and partly in axial section, of one of the couplings between the heating tubes and the inner shell of the boiler.

In the drawings there is shown a supporting stand 10 on which is positioned centrally thereof a gas burner 11 of conventional design supplied through a pipe 12 controlled either manually or automatically as is usual in gas burners of this type. Positioned on the stand 1() is the boiler 13, particularly constituting the novel subject matter of this disclosure. The boiler includes a ring-like base 14, the lower part of which surrounds the burner 11 `and which is cored to provide an open-top water compartment 15, provided with a cold water inlet 16. Resting on the base 14 are two concentric shells, an outer shell 17 and an inner shell 18, spaced apart to provide a preliminary water heating space 19 therebetween and open to the compartment 15 in the base 14. The bore 20 of the inner shell 18 provides a combustion chamber open at the bottom through the base 14 and stand 11 to receive combustion supporting air supplied to the burner. The top of the boiler is outlined by a steam dome 21 fitted to the top of the shells 17 and 18 and provided with a steam chamber 22 open to the top of water heating space 19 and provided with a steam exhaust 22. The dome 21 is provided centrally thereof with a gas exhaust 23 for discharging the products of combustion from the burner 11 after they have passed upwardly through the combustion chamber as hereinafter described.

Positioned within the combustion chamber and suitably spaced above the burner 11 is an open-top basin 24, having a flat bottom Q5 concentrically disposed relatively to t-he burner 11 and provided with upwardly and outwardly diverging sides 26. rlfhe basin is provided with a plurality of outwardly extending supporting lugs 27, resting on a flange 28 secured tothe inner shell 18 adjacent the lower end thereof. The sides 26- of the basin are spaced from the adjacent inner side of the base 14 and from the lower' side of the shell 18 to provide an annular gas passageway 29 extending about the periphery of the basin and, except for the presence of the lugs 27, providing an unobstructed clearance for the burning gases flowing upwardly from the burner.

Placed in the basin 24 is a mass 30 of readily fusible metal, preferably lead. Positioned within the combustion chamber are a plurality of steam generating heating tubes 31 similar in construction so that the de tailed description of any one will bel suilicient for the others. Tube 81 is somewhat U- shaped with a crotch portion 32 embedded in the mass of lead and extending horizontally and parallel to the bottom 25. The end portions of the tube project upwardly out of the pan and include a relatively long leg 38 in 'luid connection at its upper end with the water space 19 adjacent its upper end'. The other leg 34 of the heating tube is relatively short, opens into the water jacket space 19 adjacent the lower portion thereof. The crotch portions 32 of the several tubes are arranged as shown in Fig. 2 in two sets, in the instant case three tubes in each set, with the sets extending at right angles to each other and in superposed plane as shown in Fig. 1. The tubes of each set are separated from each other and their crotch portions embedded in the lead forming an open work grid as particularly shown in Fig. 2 so that each crotch is entirely surrounded by the lead.

A rounded bottom and elongated baille substantially frusto-conical in form is centered in the combustion chamber and in spaced position above the lead basin. This battle is suspended from hangers connecting the top of the baille with the underside ofthe steam dome and centered below the gas exhaust The baille is also centered within the skeleton truste-conical steam generator formed by the upwardly extending legs 33 of the heat tubes 31. rllhe outer surface 37 of the baille coacts with the adjacent inner side of the shell 18 to provide an annular gas passageway 38 reduci-ng in cross-sectional area from lthe lower to the upper end thereof. The spacing of the upper end of the baille from the steam dome 21 by means of hangers provides a discharge passageway 39 of the top of the baille and provides a gas discharge from the space 3S into the exhaust 23. The surface 37 also acts as a reflector which tends to divert some of theheat onto the inner shell 18 without materially effecting the freedom of movement of the burning gases in the upward passage through the combustion chamber.

rlhe ends of the heating tube 31 are secured to, and to some extent supported by, the inner shell 18 by means of a coupling more particularly shown in Fig. 3. To receive the coupling the shell 18 is provided with an aperture 40 through which is extended an externally threaded tubular coupling nipple 41, nuts 42 and 48 engaging the threads of the nipple 41 and bearing on opposite sides of shell 18 provide a rigid connection between the nipple 41 and the shell 18. In order to minimize any tendency of leakage between the space 19 and the combustion chamber, the inner face of the nut 42 is provided with a sharp edged annular ridge 44 designed to bite into the outer face of shell 18. The inner end of the coupling nipple 41 is beveled as shown at 45 to receive the outwardly flared end 46 of the end of the tube 31. A jam nut 47 is similarly provided with an internal beveled shoulder -48 designed when the nut is screwed into tight engageinent with the nipple 41 to engage the flared edge 46 and force the same into a steam tight fit with t-he beveled end 45.

In operation and assuming that there was a supply of water in the space 19 and the level of which water is regulated by means forming no part of the disclosure the boiler is started in operation by igniting the burner, The burning gases impinging against the lead basin will gradually heat its lead content and acting therethrough heat the grid embedded therein quickly producing a supply of steam which will pass upwardly through the long legs of the tube and is discharged either into the water in the upper' portion of the space 19 or directly into the steam chamber, depending upon the position of the water level in the space 19. The burning gases will pass about the basin and into the annular gas passageways between the baille and inner shell additionally heating the upwardly projecting end portions of the tubes disposed in the gas passageway and thus tending to further heat the vcontents of the tubes. As the gases pass upwardly along the shell 18 they tend to pre-heat the body of water in the water jacket and the configuration of the exposed surface 37 of the baille will tend to rellect some of the heat abstracted from the gases on to the inner shell 18 thus further tending to abstract from the burning gases the maximum number of thermal units. The construction is so designed that cold or substantially cold gases are discharged from the gas exhaust but care is exercised in designing the structure so that the discharge gases will not be so cold as to chill the steam in the steam dome.

ISO

The presence of the lead between the burner and the heating tubes tends to constitute a heat reservoir which supplies heat at a substantially constant rate to the steam generating tubes embedded therein and acts to stabilize the rate of heat supplied which might otherwise vary due to variations in the heating capacity of the burner or due to momentary variations in the temperature ojf the air supplied through the bottom ot the boiler.

lVhile I have shown and described, and have pointed out in the annexed claims, certain novel features of my invention, it will be understood that various omissions, substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spiritof the invention.

Having thus described my invention, I claim:

1. A steam generator including a ring-like base provided with an open top water compartment and a cold water inlet leading into the same, two concentric shells supported on said base and providing therebetween a preliminary Water heating space open to the compartment in the base, the bore of the inner shell providing a combustion chamber open at the bottom through the base, a steam dome fitted to the top of the shells and provided centrally thereof with a gas exhaust and provided with a steam chamber open to the top of the water heating space between the shells, a baiiie positioned centrally in the upper portion of the combustion chamber and spaced from the inner shell to form an annular gas passageway, a gas burner at the bottom of said base, a basin supported in said combustion chamber and positioned between the burner and the lower end of the battle, a mass of lead in said basin and a plurality of heating tubes each with their ends in Huid connection with said water space, the intake ends opening into the water space adjacent its lower end and their discharge ends opening into the water space adjacent its upper end and a midportion of each tube embedded in the lead and out ot contact with each other.

2. A steam generator comprising a double shelled boiler providing a preliminary water heating space between the shells and the inner shell forming a combustion chamber open at the bottom to provide an air inlet and open at the top to provide a gas exhaust, a burner adjacent the lower end ot said chamber, a basin positioned above the burner, a mass of lead contained in said basin and subjected to the heat from said burner, a plurality of heat* ing tubes having opposite ends in iuid connection with the said water heating space, and a portion of the tubes between their ends embedded in the lead in the basin and spaced apart to form a grid, one end of each tube being positioned above the other and t-he portion of the tubes, above the basin extending upwardly therefrom in the combustion chamber and in the path ofthe burning gases from said burner and a bailie in the combustion chamber centered above the basin of lead and tending to direct the burning gases from the burner on to the inner shell to preheat the water in the water heating space.

3. A steam generator comprising a double shelled boiler providing a preliminary water heating space between the shells and the inner shell forming a combustion chamber open at the bottom to provide an air inlet and open at the top to provide a gas exhaust, a burner adjacent the lower end of said chamber, a basin positionedr above the burner, a mass of lead contained in said basin and subjected to the heat from said burner, a plurality of heating tubes having opposite ends in fluid connection with the said water heating space, and a portion of the tubes between their ends embedded in the lead in the basin and spaced apart to form a grid, one end of each tube being positioned above the other and the portion of the tubes above the basin extending upwardly therefrom in the combustion chamber and in the path of the burning gases from said burner.

4. A steam generator including a shell outlining a combustion chamber, water heating means in said chamber including in superposed order, a gas burner, a basin containing a mass of lead spaced from the shell to provide an annular gas passageway between the basin and shell, a baiiie above the basin and coacting with the shell to form an annular gas passageway forming al continuation of the passageway about the basin and a heating tube having a midportion embedded in said lead and having end portions extending upwardly therefrom and positioned adjacent the said shell and in the path of the burning gases from the burner.

5. A steam generator comprising a water jacketed boiler including a shell outlining a combustion chamber, water heating means in said chamber including in superposed order, a gas burner, a basin containing a mass of lead spaced from the shell to provide an annular gas passageway between the basin and shell, and a heating tube having opposite ends opening into the water space in the boiler and a midportion embeddedv in said lead and having end portions extending upwardly therefrom and positioned adjacent said shell and in the path of the burning gases from the burner.

6. A steam generator comprising a water jacleted boiler, a plurality'of heating tubes each supplied with water, from said boiler, a gas burner. a mass of lead positioned above and heated by the burner, and containing a portion of each of said heating tubes, and the parts of said tubes within the mass of lead forming an open-work grid with each part surrounded with the lead.

7. A steam generator comprising means forming a preliminary water heating space comprising two concentric walls, a` gas burner centered in line with the axis of the inner 1 fusible metal' and having its end portions eX- tending upwardly from the basin and disposed? in the path of the gases passing upwardly about. the edge of the basin opening Ainto. the space between the walls.

8'. In a` steam generator, the combination of two concentric shells providing a water space tliierebetween and the bore of the inner shell constituting a combustion chamber, a burner in said chamber, a basin oi lead above the burner, a heating tube having its midportion embeddedI in the lead, th-e inner shell provided with an aperture opening from the combustion chamber into the water space, a tubular coupling nipple passed through said aperture, nuts in threaded engagement with said'nipple: for securing the same to the shell, one end of said heating tube flared and fitted against the inner end of the nipple and a jam nut for securing the flared end in steam tight engagement with the nipple and said nipple constituting a continuation oli said tube opening into the water space..

9. In a steam genera-tor, the combination of two concentrici shells providing a water space therebetween and the bore of the inner shell constituting a combustion chamber, a burner in said chamber, a basin of lead above the burner, a heating tube having its midportion embed-ded in the lead, the inner shell provided with an aperture opening from the combustion chamber into the water space and a demountable tubular coupling intruded through said aperture, securing one end of the tube to the inner shell and constituting a continuation of the tube opening into said water space, a tubular coupling nipple passed through said aperture, nuts in threaded engagement with said nipple for securing the same to the shell, one end of said heating tube flared and fitted against the inner end of the nipple and a jam nut for securing the flared end in steam tight engagement with the nipple and said nipple constituting a continuation of said tube opening into the water space.

10. A steam generator including a vertically extending shell oulining a combustion chamber, water heating means in said chamber including in superposed order, a burner,

- a. basin containing` a mass of lead spaced 'from the shell to provide an annular gas passageway between the basin and shell and a U-shaped heating tube having a mid portion embedded in the lead in the basin and extending upwardly therefrom, and portions of said tube positioned in the path of the burning gases from the burner and secured to and supported by said shell.

ll. A steam generator including two concentric shells providing a preliminary water heating space therebetween, the inner shell outlining a combustion chamber, water heating means in said chamber inclu-ding in superposed order, a burner, a basin containing a mass oi' lead spaced from the shell to provide an annular gas passageway between the basin and shell and a heating tube having a mid-portion embedded in the lead in the basin and having end portions extending upwardly therefrom, positioned in the path of the burning gases from the burner and discharging attheir ends into said preliminary water heating space.

Signed at New York in the county o'l New York and State of New York this 7th day of April A. D. 1927.

EUGENE J. ROVAN. 

